Screw-cutting die



(No Model.)

1?. H. GLASS.

. SCREW UUTTING DIE. No. 315,728. r Patented Apr. 14, 1885.

. y l I F I 3 Q1 .5

WITNESSES: INVENTOR ATTORNEYS.

UNITED STATES PATENT OFFICE.

PHILIP H. CLASS, OF GREENFIELD, MASSACHUSETTS.

SCREW-CUTTING DIE.

iESFECEFICATIOlT forming part of Letters Patent No. 315,728, dated April 14, 1885.

Application filed May 2, 1884. (No model.)

T 0 e255 whom it may concern:

Be it known that I, PHILIP H. CLASS, of Greenfield, in the county of Franklin and State of Massachusetts, have invented a new and useful Improvement in Dies for Screw-Cutting, of which the following is a full, clear, and exact description.

My invention consists in screw-cutting dies set eccentrically in the stock or holder in a manner to allow of their opening and closing, so that screws of different depths or sizes may be out, as hereinafter described and claimed.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar letters of reference indicate corresponding parts in all the figures.

Figure 1 is a face view of my improved dies and holder, partially in section. Fig. 2 is a bottom view of the holder, and Fig. 3 is'a cross-section on line a: so of Fig. 1.

The holder or head A is of usual form, except that the circular mortise in the face receiving the dies B B is formed eccentrically to the aperture going through the holder. The dies B B are formedso that they are slightly separated on a line through the cen ter, and are held thus by taper-pointed screws a b passing through the sides of holder A, with their points entering the spaces between the dies. The cutters of the dies correspond in position to the aperture in holder A, and consequently the central point between the cutters is not the central point of the semicircular dies. By turning in the screws or and drawing screw 12 outward to the same extent the cutters will be closed together, and by a reverse operation they will be opened, so that screws of different sizes and of different depths of thread can be cut. On account of the eccentric position of the parts the adjustment is given a wider range, and the turning in of either screw has always the same effect, either to spread or close the dies, as the case may be.

Having thus described my inventionl claim as new and desire to secure by Letters Patent- 1. The screw-cutting dies B, of semicircw lar form, having cutters centered eccentrically, combined with a holder constructed to re ceive the dies, substantially as described.

2. In a screw-cutter, the eccentric dies B, eccentrically-mortised holder A, and screws a I), combined substantially as described.

PHILIP H. GLASS.

Witnesses:

LYSANDER BARNES, LOUIS H. STARK. 

